SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8528114c5b7cd36398a2e864a42eea897b0af45c4895f71876d2dfd8acbfaabe' 
  AND token = 'PoNBwsNO5TFXpT6fZ0BoCkwi0dyMF9GkLrK/Nn1UPfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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