SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '890c1344107c433786629501e51402635b7282ca2fb198f61d087ead31d4578f' 
  AND token = 'b7LtvRSZyKD24vYyUASqdVSekQLGr45JF+2gzw9SUuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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