SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c38c8d2384c3010398621ba8838c8198fab75bebf768da329415906aae5e4e9' 
  AND token = 'iaZ5y0JgZU8mo0/PVsTYmDLBXsGF84UXtHX3KJbyz1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}