SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4abba660dd8f5c95f6a7c410a0961d515e429d00b67812ecbb5362cda0dc3d36' 
  AND token = 'Iu/hg2pUt9l3Xp+DEQXwVdDVCc6j+bAR8B2uYqTmvd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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