SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc589a8cc5a939c6ca31fb621e0123007d64a3fa600165d493ada5c1cb26799' 
  AND token = '+j5gA+raGigXGzTkgG6CRmzOoudPzXSA0zafIWhHwrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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