SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a73bf4724583cb5176016a73c47a304582e2ce100a4ae5882099b5a1d50e96e' 
  AND token = 'pTvoGU6GAjLErMTv/dWCV87HHAsTouu1cv2OPXZba2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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