SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '541d0083758d4ffdc064e34065e6b096412ed1a0945c15f2e282dd01b3a52a04' 
  AND token = 'nVaSWbAGOYmJrmU7KO3esCxYT67VnJUpQc9dgf/0JC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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