SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb7f69356c0a0c7f8798a9b0d3865bdc5f8e1e9a2736502252ccb9b8840da400' 
  AND token = 'X2w/pCZILFZ+ulguvMYEFKtrs3T3u5h6vAwavhn/fm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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