SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20adf8128ba64aadc314234152fc85498fcabda0497fc833010408a0b8bb3793' 
  AND token = 'Jd9J8BHvIkZrQ8zI7mNQI96JfY0QfmgYqlet2FN+s4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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