SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5dc932a9d70e98bce68a4328c71172e83572ffe0540e53059ea05f600236009' 
  AND token = 'soO90quMirJ/KO/wCNYDCswWlcabHekV/XOc7TdfcGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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