SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d3f16816b386951e502795b389eae2255790c6b458d648d7a3f99f278874c8d' 
  AND token = 'nAHdPJu5CXykuYaBibtNwUJ4UcOYJFt2MH8l0adSBjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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