SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d004cba8981309217a839d3c2bc2cd85f7dcb083525bca49224039abf416bc3' 
  AND token = 'GYNn3pGIburJV3h3dH2BVDSVQVkVxAoZWdSaC28zE4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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