SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91f0055a0a46bc1431dc815ba0202189babda3928e5b95c2e220c88a1ab56f4' 
  AND token = '7FEgZap48BnnvszEeGq16rgDoRoH0jjF93/XK++/0Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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