SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '265ab098b4b486c95a38674240437a811c6317db723c00c68214b9270ae1bf2a' 
  AND token = 'BfMjIOsXcUZL+rocMK37Uj8AS4aA1Yb87zYIKN2qfZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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