SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'efd2459f8d1d38e2df2c9882d8134eca78619bc1101f6453a8d23728f7c2a5e7' 
  AND token = 'o8/A7OHpfZQCaTSj6l1cwux83Nj9v+jKnVxPqnJEJDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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