SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a595d5b9a0fc999e7bea680402a17c36b53a62a3d201615010cccc6fed8f031' 
  AND token = 'dd8H8MBZOLCUygkkN4J8M6pvW4ZwLoS4G53jerYpv0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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