SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b67687f10ed951c501c7b1b764443405c6029703ec653b95677a4200aa2fee4' 
  AND token = 'TNPW0Qf6EfoKzdvcJ5UEjESDsYfsQzVT5WqldpHlCw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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