SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f85a0302373338f5a47c58bad62a1f3bb275828cc978d268dc5f86bbae1681c8' 
  AND token = '/VRdGR5j//1UCIVgCqW4mBgD0DQTzVOVIx1tgXLmBlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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