SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52315297f6ce4d68cc3a1ddd7eeb1caa52b72c8a41aafbcbb424fa2a4331e35b' 
  AND token = '2PjhYkY7unqKVH6wCJBqbN8TBfcICLd/Ql9dy3dQ9qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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