SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ef4eba3d5f9ce5bad317462efa6d67fd8a3ef830522f5bf2f45d243731b71af' 
  AND token = 'ydu/BJzDGYi9STp8yEbrp7iwBhzUsbu+2un5MUpp3ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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