SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd69dff6cf4a142dde14740892af913978ab25f3e56fa320a85de2fa95de00a42' 
  AND token = 'UZpxrwQoSnMK7LqTNd3yPHpVBn0YdFbckyI+t0twxtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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