SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e48590486dd27a64a6a540634f5f5fc3758124a30467c76cfa6d7cde18fb3064' 
  AND token = 'yfl9gQsTer+8vGrYK2qk3dgFjpmLlXXVuhAgOtrXYEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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