SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '441bac53ff15f83f4d38da2ff94d28eefe7cdbc637cc22194ee9c46bcf58ddce' 
  AND token = 'GagzFjZsxth7jH/pUtb4jicxWVgRuQ4LnLpjGEPaqL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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