SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e03daeea8f5ec934faab77a5e7fc2c6869a779af7aecb17c458ca697967eba50' 
  AND token = '+I1WIdTScftR/5I6NKGd5rKovQ7uy7GJZorLbMcAisM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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