SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188baf7215a6587434c2f7152228dae05dfeab1bb2d6d145985acc35526e6af2' 
  AND token = 'y5u/ujc0wfUdf4BVgNdnARgQiTNhm0ePHYToI5XUy6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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