SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40da9d52915343555f5a18faf9a7ebc581f8fdde0ff4305660aaa1b8c0cf2b0' 
  AND token = 'V57PzmJXvC2U/kmpxdPogLRCusjG4YnpVeg/UnYRTSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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