SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09083218d9d01cc882cc87988b21847915b771e9356591e5773521ab711fc714' 
  AND token = 'gbG10sz/I4Rt6GXKguse+ASTK43asfQ/mCsvbnTFyM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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