SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cde09a11ed117b0d87718800773d2c990cb42eb8dab99a5ab0095a45290463d' 
  AND token = 'SaZA8/an6P7ms45aF+JIoQez1pYMcN+0uumbTZqbnNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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