SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4d73f070ce07c5bd335c0a26d0f4bbe986dfb18cc5ec6eef388134885a5079c' 
  AND token = 'MgJ2bN8EupXm/f57PNITUlHtRkt3nHs5yEWIcjsmgnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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