SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a0cebcdf579e970513962eca111be938e6451b77a8d4d7012e327fe62f66a6a' 
  AND token = '73MyG2YPGAMF1MFllIB9BO84emDbYtIT/IGosBUFrzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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