SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f60e3e21b83d61b8f1468e590b437ae746baff1c267a9ee23da999ac7c6799' 
  AND token = 'VRZdQTThVmqwiWC/gjVNJXrlaIu3dlScYFUE+agPN8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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