SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96b207de9a34a410f266983df838471917439145d735aeff68d08d21027e22d0' 
  AND token = 'fKvw3Mo/353F9FanhzaCt0vRiwUOoQ1HFtTdQ9H5qZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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