SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e928da9a3ce573508bd29dd235bf7c595739bd33acceb1a77956c5a11d76e30c' 
  AND token = 'kreJpaGUznM2kRoHJ3idZ7IGCfMTWL+Cx7rIV7coOes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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