SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f9e9cab66e97f1aa9113c832bd094fde8a12ce8ecd63aed1937a3a081296be73' 
  AND token = '5t0ePiRgUeQWHn8JrQ3nQ9oIZ/SMMGusYi8bHzdF8f4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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