SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd600f04c22b98d263bb212b785e106126aaa296f77d662fb13a18b463f4562c3' 
  AND token = 'Yc3YKzHrnxqOcdeSmSgFFUcDRgcDzB6rEOeaY2v6dTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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