SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b70c47bdd34da384703b1e739c9e565a817bdaed17d320efb804dffae15c32b' 
  AND token = 'zqOLRyJUO0lwOQn39E9DnMxEk7C6niBhfZjNtELXORU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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