SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5801454256dd70fd8f48acddcbd0208b2672a9e1b8be7acf452593c603effd1' 
  AND token = 'Hcg5MpblyXFCOgWa6+V6lLQ+Plmw876SRLoIxMyQNjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}