SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bffe34a83d136d07272562da8d6c4363eeefabd37841c1eaf5f378b345ebe69f' 
  AND token = 'irU8YklqZA2Atz92rINw1zmXy6awWonSIfQzXm7lc9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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