SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4147d81f98d186660ee75d1dd9dd1e82c551c271b5e1d39855f6d67454ddfde8' 
  AND token = 'usCHt0ehDIzwLDWVGvu9601rqSgkJd62WR2BmKEaBJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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