SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c2495da66bdcc6e415c5463785c1cc1aa9cdb692b0d6373b3ab2028d216868a' 
  AND token = '7tG08aa+mkGbc0lhmBibRpYanrkdeyCqVpUmr2I0vbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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