SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ede456837ecded01a930ac8fcf024a9908391c155a701c4ab86c123873ceac40' 
  AND token = 'McxNjTHwmugLZiPwCpXM1YL5cwJDm1VLvjsMdbdb4UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}