SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba168ed54cef0b510209fb3d370e236f3ffcd9ab4132dc348f2dac8993794af6' 
  AND token = 'nBylY5oJAqKMSgSgFuoYnhwiLoiZsOgt2eDHC52IiLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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