SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2be475025aa352d19608e1a9b37ac9606ec023f16856da6303908ca90b6aac1e' 
  AND token = 'RXA6AL5Fuk4GsEEPPzAqaZ4bLqKo+Z/o5uHCkhuS1yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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