SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908fecd4d8546e1d091ed3418f8cc6acfbc08b8a77d5b2977adbdba72341a982' 
  AND token = 'H/UYmnfQU/fkV6isT9nsma2NSjMDAbJEZPJBpgy2VCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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