SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1801c85e351159dc1a75e997743a5a76da49e6a0e046400f92338e854fa3816' 
  AND token = 'FwWAdvAvFsKA/GKKo8Mw2nq7EfzrZs3qs//T3EmiMoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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