SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f244ff158fc730fbfe7993208fa6211dc9dfb9224f8a0b1ca9cde3ef8cc55099' 
  AND token = 'UvbnvlObpxLRZ19lfnZHFUuMXaO/pyT7mrg0V6wrR0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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