SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9248e0e2246d13bb978708efaa05143b92d818cbe4bf7feba3000df64ab99406' 
  AND token = '11wFIYiDA/FXR3iJm5YybM8KfwRENdjB+E1cu4iDBT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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