SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd650f98653a0e66ffbd6ce651a95746dfee6e5ef4a37ebfc742f66bd0a188809' 
  AND token = '/+qrZ+ZyKHV3YMSjopZ5tjTSQnXgKUdKA4nUpLnLqmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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