SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d769621f401062b72e837b19e90186fa2cd8961c71ce0f12d1a6bab4aef4e18' 
  AND token = 'xLhFSAHONiuv5AuodmpnLPwOKmmnY5/rlyKugDdUbk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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