SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae6ee5840880dd1607b09b1c49889b301801f3f919eb12210db68957fd479214' 
  AND token = '8nEaz+nnnD2KNLpvAuMj8SZmqioyl85t8XBKbFAiFws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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