SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dfe9f99524c3485cc9be9e2abd05216d8dde0cfc563e52c10fd21367fd275ede' 
  AND token = '7VtACQp4/RGTRM/hEtvStROIMkNyD9ILGSBsqyDMiOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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