SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286695b17d395e64f494f7566617a7e92f0ea42ca68d477818e488658ad35faa' 
  AND token = 'hCABBll7C6XsiXkxC++X6x9vTuNEMzRsqwnAc/VV7Jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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