SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bc31f88aa23a0303c306a09a4bae517585102807fc8a571001b6eda736506c2' 
  AND token = 'OBldlPCsv+kwUB2iMTXsEOon4ZVNW3/h2Iq8sB6nKTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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