SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '265d12b35e51281931cfa7020e39c1b2b5c330e269a22bd08d1395f7080a8ec2' 
  AND token = 'oYjDZQ38mwYQtwt3lOBc4MgcChtjyUb+5UlorFw8iMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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