SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb7005fdec97bb67913528ab9a018a2d9d0b95dc31cedfd81d5c980a87cb2f51' 
  AND token = 'NdN4BHEaTdTnKOpiOZtnAbs8OgYaLfzWLXTWRxIGo0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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