SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afea353f8c6a4ab076d5ede411572ac05828f2d948fd19e17cbadaa1b52a4bc3' 
  AND token = 'KLE+qvBKqhCLJh+YKqG1EGmLrLUJP2j+BbU4DblxQB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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