SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca661b5f75b83bdb60893c866f037731c6cdaf3e31903ad55c7a7bdfdb708131' 
  AND token = 'chbj8Gok5Tt8hdQF72cYotFKFOX+86yGcun64LlRNoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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