SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccd5398df51b6d8e8d5ca80e4d22e325156e910339d627abeff22ba858c45be8' 
  AND token = 'RbEMjn3QjBtzTnMxAeY/AwLpzkgL/3g2V+fAhKtkhRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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