SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a8a3f2d5281098662fc34f443693c7c55238d278a51fb8dbb5ce5e75dccf6a6' 
  AND token = 'JSaOfu/vFzjOiMOAioBZf/4YmWQNuszD6IHoMYjxidg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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