SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce79e9f64ded38c7d37044c2ffec376d243fa2852ae871f55fbc2677713eb64' 
  AND token = 'F1GzsAiNi/fBgZ9iCXJalPuxJnV0HI9KBoUVvaxwZ1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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