SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb3c441d30205c04312667aa562b9930892de1f44c236ee7ebc304d842baaef6' 
  AND token = 'qvMh2mtTHdEg/KhcUTPt+25/5f+/JiSmz84uXChyqDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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