SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '454909c9e438543644cb43bbd3941d3ec7e9356c9c69a2ad9935892f356c8387' 
  AND token = 'aEWIVIVikTHkkPVF3pvgRwjF+97FKOBDg1jHKKLddyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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