SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd726dd0cdb6ee5f14e1f8e4e1059e9432d0d8f71bbaf3f3064804b61617dd983' 
  AND token = 'w7Jxy1uZW4msxKlx27YtV/i4dSyUmsMMOVF6GwpD7Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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