SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00c2f29eb529a0d927b4f7069eb11e730d56b9671ac1ba33fef87d06d3689cf8' 
  AND token = 'FN+eSBIeoN+GgEz/XeFTjJFnSrLGJTpNelya9DSseFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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