SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c892ef4e216120fb93fde5456b907664bb3cdc621028aa1fcbda621dc4676aa9' 
  AND token = '37tLtXAuA1JXD25qoBkc7XkYRtNDMIpXoKYQXyHxlAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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