SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f7b5889603cab96c9723fbcffb7b352f0f9e9b3ede6121adc763bedffbf3212' 
  AND token = 'GV9rSTG+EIUAyqk5rGFUnog9iOvXsr1yKxzTEzkrvdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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