SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2531d6035602377f62a6179748c939509d4ea0bb24edf81b0a8d1da167f4415' 
  AND token = '7j2DkUR+7UKNvoeQ70WoCkd0e19XaTHAN74qk+Ve+Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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