SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9bfeab44fec9176503a52a2faf91e00f0785b25ebb9b5f518ce8696a618df8b' 
  AND token = 'WfE5PkAs1z5NTUwis8rXZyDLliGrzBbx/Tg+DFJeg7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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