SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd7312783afcf8c94e9d8b34bddf68f884f6124185ab6630de4336d64948a0d6' 
  AND token = 'lzdvdhTzTMjajfVccViLmU2UfaUUUnWMAPM0mTmGMbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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