SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c16187cb14c92454129f2391f2f2f9fe0f79c222ec315e2f8a3352ac0456a0a' 
  AND token = 'CgOAWxaGqWezZTxZ+/IxS2F7LXnU2G3JvwhrIehjJYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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