SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ebbd253210dd6b3fd137f773b4c8b3fb8117b99e908ec4428daf1da961cf77c4' 
  AND token = 'W5qX3PQjpTMrey2xMPQ0RUOLDoltIC2wIzKGj2tu8pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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