SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c38e2bfcf826f3204710e2387a1152e2d6416fc869fa7e29bff0269839c0a29' 
  AND token = 'X2dTBHWFm2yBsipnxRohmnbR5a+YeH1aODnkrQWnpm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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