SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62e85c2cffed01eb264b6059061b6cb85a1382540f980dce21b0f8d12d19bb53' 
  AND token = 'H67VKLpjUy5H72oPqbCmi+SSSSUXUcJCiMgmT/MjvRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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