SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '258fb7cff9f2f0ffa297acf4dc843ce59793ce9aafe276f693f33ae9dcd34c64' 
  AND token = 'QxCE1Ab7xJQWGJJSBdE7FxPDli71hzmdNDwpjdbH9vY=' 
  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"
    }
  }
}