SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca0a7806e5533b25996915906607635852b98bc846ff20b19e9a6325624c9940' 
  AND token = '7f3PHRhTL8TQfCO0DpT8shEU0jmVUZZh7kp/gvxGSCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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