SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2314d63a64e4800b07f4507625ad1898a35976083cb58710d3834f294b05062' 
  AND token = 'AYxPqjvtBDAoAhQNi2mlNbbmlBIdf0wd7+xEqgpvzdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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