SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'de980de26635abac9467232532ba07b66db11e867f98d5e5b2d69aeaf5978848' 
  AND token = '5tzUv1cZKFd9IiNVfnXkRNTITPVXFYFjaXgYDIVHZo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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