SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '045414aec55d08ddce54f0f2def61001befde01a4cd8bdb3805321bc2b7033f9' 
  AND token = 'xA3Vr2kQBcULtzrV+sNWuSlhrNAq5ZRLgW1Sh821ArQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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