SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cfd5fb0723daa00d36b95e96fe188a92cd6b2f837d3a51c60efdcd3c9aff87eb' 
  AND token = 'tLThJi+WWoOGRT3Q1X5N4646zX2JJugZ3rOBOkf5yMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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