SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a2374d6a83369fe9fd7a777cf5d32df8f98e48b61314c066fc6d752a3682fd5' 
  AND token = 'iwwdpe5nORu28pvZvqhctBMMOUEHPCZcMNYqHPVmQqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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