SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7b93f7db87c0a83c23d82415835d704b0354fd910a856023c96b56e95510fa45' 
  AND token = 'VFxNFRLDP5NqNPpjz765m1icHIMPwSInWGY3ZQOtT4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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