SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c50c8627d5a1d61b5792553cd06c61476a8ba36e06614d7995b937b5968b49' 
  AND token = 'zchFjA53FE9rdUCA0ubVanWStuUFiv/QaMRePjyNv7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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