SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26a07be74904cb6dcc1b4d045324424ff1faeb6a4f2ac953a2c95882ac9e9ddf' 
  AND token = 'W7cwG057GXOLl4pQ5mkHAa5PDfdB2N2P8rIeMTMorek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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