SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bc6dc59c17cdc15102afa950b006d4ad5450f30c21be5b46de5f87fa9871246' 
  AND token = '53/yESwqgpUsRkAkj/gAxVfG1CDEiEYNbr2dtUooWek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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