SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '871ed8526c44af26fd8146c266255cdbac7c519befdefaf8c0a07d24bdd16c0c' 
  AND token = 'B7LsUcI/uTUROswqwpW+PNEgsyw4zlOSr9JKHLjhF2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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